Alkenes are one of the most abundant fine chemical feedstocks, readily accessible from both petrochemical and agrochemical sources. Due to their availability, a multitude of methods have evolved for converting alkenes into the fine chemicals that provide modern society with medicines, agrochemicals, materials and plastics (B. Trost and I. Fleming, Comprehensive Organic Synthesis (1991). One of the most important synthetic reactions of alkenes is with acids, comprising a cornerstone of reactivity in organic synthesis. Moreover, this reaction is integral to the catalysis of important processes such as cationic olefin polymerization (G. Odian, in Principles of Polymerization, 372-463 (2004)) and the addition of nucleophiles to alkenes (Trost and Fleming, supra; M. Beller et al., Angew. Chem. Int. Ed. 43, 3368 (2004)). The regioselectivity of these addition reactions is dictated by a chemical principle, known as Markovnikov's rule, whereby acids add across nucleophilic carbon double bonds to give a preferred site selectivity (M. B. Smith, J. March, March's Advanced Organic Chemistry (2001)). Generally, the alkene and acid polarities align to give the chemical branching depicted in FIG. 1, precluding the direct formation of the opposite, or anti-Markovnikov, isomeric adducts. This has limited the types of chemical structures that can be directly forged via this fundamental organic transformation.
To reverse Markovnikov regioselection is no trivial task and has been cited as one of the preeminent challenges for catalysis in the new century (J. Haggin, Chem. Eng. News 71, 23 (1993)). After decades of effort, the most viable methods are indirect (e.g. alkene hydroboration and oxidative functionalization) and are designed to circumvent the strong bias against the anti-Markovnikov products. Recent disclosures of transition metalcatalyzed direct anti-Markovnikov addition reactions have made strides to reverse this trend but are limited in scope with respect to both acid and alkene (M. Beller et al., supra; G. Dong et al., Science 333, 1609 (2011), M. Utsunomiya et al, J. Am. Chem. Soc. 125, 5608 (2003)). The development of a general and straightforward catalytic strategy to access anti-Markovnikov site selectivity has remained to be identified.